This invention relates to an improvement in a correlation function computing device which is adapted to compute a selfcorrelation function utilized as a characteristic parameter in voice recognition.
Assuming that X(n) (n is an integer) represents a time series of a voice waveform and W(n) represents a window function used for sectioning the waveform into short intervals, a selfcorrelation function R(.tau.) used as a characteristic parameter in voice recognition is ordinarily expressed as follows. ##EQU1## wherein .tau. represents the order of the selfcorrelation function thus computed.
A heretofore known device for computing the self-correlation function to be used as a characteristic parameter in voice recognition has been so constructed that it includes a plurality of multipliers and adders, the multipliers calculating the product terms in the above equation (products of the window function and the digitalized voice signal), the adder calculating the sum of the thus calculated products, with the product-sum thus calculated stored in a memory device accompanying an address control circuit.
Such a conventional device for computing the self-correlation function has been found to be disadvantageous because it requires a number of costly multipliers and is inevitably complicated by the necessity of address control each time the product-sum is stored in or read out of the memory device.